[v5.15] possible deadlock in sys_mbind (2)

Hello,

syzbot found the following issue on:

HEAD commit: c16c81c81336 Linux 5.15.178
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14dcfc54580000
kernel config: https://syzkaller.appspot.com/x/.config?x=3ca28fba9b2e5c5
dashboard link: https://syzkaller.appspot.com/bug?extid=9c41b8900a32c1dcc9d8
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3f2947e5e4dc/disk-c16c81c8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7034800fdaa8/vmlinux-c16c81c8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/42337be7c213/Image-c16c81c8.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

======================================================
WARNING: possible circular locking dependency detected
5.15.178-syzkaller #0 Not tainted
------------------------------------------------------
syz.1.256/5691 is trying to acquire lock:
ffff0000f00ba090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27

but task is already holding lock:
ffff0000c7f0a958 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
ffff0000c7f0a958 (&mm->mmap_lock){++++}-{3:3}, at: do_mbind mm/mempolicy.c:1299 [inline]
ffff0000c7f0a958 (&mm->mmap_lock){++++}-{3:3}, at: kernel_mbind mm/mempolicy.c:1472 [inline]
ffff0000c7f0a958 (&mm->mmap_lock){++++}-{3:3}, at: __do_sys_mbind mm/mempolicy.c:1479 [inline]
ffff0000c7f0a958 (&mm->mmap_lock){++++}-{3:3}, at: __se_sys_mbind mm/mempolicy.c:1475 [inline]
ffff0000c7f0a958 (&mm->mmap_lock){++++}-{3:3}, at: __arm64_sys_mbind+0x5c4/0x13ac mm/mempolicy.c:1475

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&mm->mmap_lock){++++}-{3:3}:
__might_fault+0xc8/0x128 mm/memory.c:5355
reiserfs_ioctl+0x110/0x4b8 fs/reiserfs/ioctl.c:96
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #0 (&sbi->lock){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3788 [inline]
__lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012
lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
__mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
map_block_for_writepage fs/reiserfs/inode.c:2396 [inline]
reiserfs_write_full_page fs/reiserfs/inode.c:2593 [inline]
reiserfs_writepage+0x7b0/0x2f54 fs/reiserfs/inode.c:2745
writeout mm/migrate.c:837 [inline]
fallback_migrate_page mm/migrate.c:861 [inline]
move_to_new_page+0x680/0xcf4 mm/migrate.c:912
__unmap_and_move mm/migrate.c:1077 [inline]
unmap_and_move mm/migrate.c:1218 [inline]
migrate_pages+0x1a38/0x3280 mm/migrate.c:1495
do_mbind mm/mempolicy.c:1325 [inline]
kernel_mbind mm/mempolicy.c:1472 [inline]
__do_sys_mbind mm/mempolicy.c:1479 [inline]
__se_sys_mbind mm/mempolicy.c:1475 [inline]
__arm64_sys_mbind+0x1004/0x13ac mm/mempolicy.c:1475
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&mm->mmap_lock);
lock(&sbi->lock);
lock(&mm->mmap_lock);
lock(&sbi->lock);

*** DEADLOCK ***

1 lock held by syz.1.256/5691:
#0: ffff0000c7f0a958 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
#0: ffff0000c7f0a958 (&mm->mmap_lock){++++}-{3:3}, at: do_mbind mm/mempolicy.c:1299 [inline]
#0: ffff0000c7f0a958 (&mm->mmap_lock){++++}-{3:3}, at: kernel_mbind mm/mempolicy.c:1472 [inline]
#0: ffff0000c7f0a958 (&mm->mmap_lock){++++}-{3:3}, at: __do_sys_mbind mm/mempolicy.c:1479 [inline]
#0: ffff0000c7f0a958 (&mm->mmap_lock){++++}-{3:3}, at: __se_sys_mbind mm/mempolicy.c:1475 [inline]
#0: ffff0000c7f0a958 (&mm->mmap_lock){++++}-{3:3}, at: __arm64_sys_mbind+0x5c4/0x13ac mm/mempolicy.c:1475

stack backtrace:
CPU: 0 PID: 5691 Comm: syz.1.256 Not tainted 5.15.178-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call trace:
dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
dump_stack+0x1c/0x58 lib/dump_stack.c:113
print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2011
check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2133
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3788 [inline]
__lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012
lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
__mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
map_block_for_writepage fs/reiserfs/inode.c:2396 [inline]
reiserfs_write_full_page fs/reiserfs/inode.c:2593 [inline]
reiserfs_writepage+0x7b0/0x2f54 fs/reiserfs/inode.c:2745
writeout mm/migrate.c:837 [inline]
fallback_migrate_page mm/migrate.c:861 [inline]
move_to_new_page+0x680/0xcf4 mm/migrate.c:912
__unmap_and_move mm/migrate.c:1077 [inline]
unmap_and_move mm/migrate.c:1218 [inline]
migrate_pages+0x1a38/0x3280 mm/migrate.c:1495
do_mbind mm/mempolicy.c:1325 [inline]
kernel_mbind mm/mempolicy.c:1472 [inline]
__do_sys_mbind mm/mempolicy.c:1479 [inline]
__se_sys_mbind mm/mempolicy.c:1475 [inline]
__arm64_sys_mbind+0x1004/0x13ac mm/mempolicy.c:1475
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584


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